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// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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// KIND, either express or implied.  See the License for the
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package org.apache.doris.nereids.trees.expressions.functions.scalar;

import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.AlwaysNotNullable;
import org.apache.doris.nereids.trees.expressions.functions.ExplicitlyCastableSignature;
import org.apache.doris.nereids.trees.expressions.functions.ExpressionTrait;
import org.apache.doris.nereids.trees.expressions.literal.StructLiteral;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.types.StructType;

import com.google.common.collect.ImmutableList;

import java.util.List;

/**
 * ScalarFunction 'struct'.
 */
public class CreateStruct extends ScalarFunction
        implements ExplicitlyCastableSignature, AlwaysNotNullable {

    public static final List<FunctionSignature> SIGNATURES = ImmutableList.of(
            FunctionSignature.ret(StructType.SYSTEM_DEFAULT).args()
    );

    /**
     * constructor with 0 or more arguments.
     */
    public CreateStruct(Expression... varArgs) {
        super("struct", varArgs);
    }

    /** constructor for withChildren and reuse signature */
    private CreateStruct(ScalarFunctionParams functionParams) {
        super(functionParams);
    }

    @Override
    public void checkLegalityBeforeTypeCoercion() {
        if (arity() == 0) {
            throw new AnalysisException("struct requires at least one argument, like: struct(1)");
        }
        // for all field we do not support struct field with jsonb/variant type
        children.forEach(child -> {
            if (child.getDataType().isJsonType() || child.getDataType().isVariantType()) {
                throw new AnalysisException("struct does not support jsonb/variant type");
            }
        });
    }

    /**
     * withChildren.
     */
    @Override
    public CreateStruct withChildren(List<Expression> children) {
        return new CreateStruct(getFunctionParams(children));
    }

    @Override
    public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
        return visitor.visitCreateStruct(this, context);
    }

    @Override
    public List<FunctionSignature> getSignatures() {
        if (arity() == 0) {
            return SIGNATURES;
        } else {
            return ImmutableList.of(FunctionSignature.ret(StructLiteral.computeDataType(children))
                    .args(children.stream().map(ExpressionTrait::getDataType).toArray(DataType[]::new)));
        }
    }
}
